This invention relates to a window balance system for use in a pivotable window assembly.
This invention relates to the field of tilt-in windows. More particularly this invention relates to a balance shoe of a window balance system used in conjunction with a pivot bar mounted on a window sash for rotating the window sash relative to a window frame.
Typical pivotable double hung windows include two window sashes disposed in tracks located in a window frame to allow vertical sliding movement of the sashes. Pivot bars are provided to allow rotational movement of a pivotable window sash about the pivot bars to facilitate cleaning of glazing. To control vertical movement, window balances are used so that the window sashes remain in a position in which they are placed. Balance shoes are used to guide the rotational movement of the window sashes with respect to the window frame. Typically, the balance shoes are coupled to window balances with a connecting member. See, for example, U.S. Pat. No. 6,119,398, entitled xe2x80x9cTilt Window Balance Shoe Assembly with Three Directional Lockingxe2x80x9d issued to H. Dale Yates, Jr., the disclosure of which is herein incorporated by reference in its entirety.
One of the problems with balance shoes and window balances for pivotable double hung windows is that they are difficult to install. In order to install a pivotable double hung window with balance shoes and window balances, the following installation steps typically must be followed. First, before the window frame is assembled, the balance shoes are inserted into jamb tracks. Next, connecting members are used to attach the balance shoes to the window balances. The balance shoes generally have an opening to accept the pivot bars that are mounted on window sashes. Finally, the sashes are made operable by inserting the pivot bars into the balance shoes and rotating the window sash up to a vertical position in the jamb tracks. The installation process is rather complex and difficult. Repair costs for replacing balance shoes are also significant. In order to change a malfunctioning or failed balance shoe, the jamb tracks either need to be deformed or replaced to gain access to the problematic balance shoe for removal and replacement.
In general, in one aspect, the invention relates to a balance shoe. The balance shoe includes a frame, a locking member at least partially disposed within the frame, a cam in communication with the locking member, and a connecting device for attaching the balance shoe within a window balance. Embodiments of the invention can include the following features. The connecting device can include one or more retractable or resilient tabs that engage the window balance directly. The frame can further include a frame pocket sized to receive a fastener. The cam can include at least one camming surface and a keyhole opening for receiving a pivot bar attached to a window sash. The cam is at least partially housed within the frame and is disposed within a space enclosed by the locking member. Upon rotating the cam with the pivot bar, the locking member engages the window jamb. In one embodiment, the locking member includes two opposing ends integrally connected by a spring member. The cam is located within a space between the opposing ends of the locking member, and upon rotating the cam with the pivot bar, the opposing ends engage the window jamb. In another embodiment, the locking member includes a plate, which is parallel to a back surface of the frame. The cam is located within a space between the plate and the frame such that rotating the cam with the pivot bar forces the plate to engage the window jamb.
In another aspect, the invention relates to an inverted window balance system for use within a pivotable double hung window assembly. The inverted window balance system includes a rigid U-shaped channel with a plurality of openings in the channel walls for securing the contents in the channel, which include an extension spring, a system of pulleys, a cord to connect the extension spring via the system of pulleys with the window sash, and a balance shoe. The balance shoe includes a frame, a locking member at least partially disposed within the frame, a cam in communication with the locking member, and a connecting device for attaching the balance shoe within the rigid U-shaped channel. Embodiments of this aspect of the invention can include the following features. At least a portion of the balance shoe is disposed within the rigid U-shaped channel. The connecting device can include one or more retractable or resilient tabs for engaging the rigid U-shaped channel. The retractable or resilient tabs can partially extend through at least one of the plurality of openings in the rigid U-shaped channel. The balance shoe can be further secured to the rigid U-shaped channel with a fastener that interfaces with a frame pocket in the balance shoe. The cam can include at least one camming surface and a keyhole opening for receiving a pivot bar attached to a window sash. The cam is at least partially housed within the frame and is disposed within a space enclosed by the locking member. Upon rotating the cam with the pivot bar, the locking member engages the window jamb. In one embodiment, the locking member includes two opposing ends integrally connected by a spring member. The cam is located within a space between the opposing ends of the locking member, and upon rotating the cam with the pivot bar, the opposing ends engage the window jamb. In another embodiment, the locking member includes a plate, which is parallel to a back surface of the frame. The cam is located within a space between the plate and the frame such that rotating the cam with the pivot bar forces the plate to engage the window jamb.
In still another aspect, the invention relates to a method of installing an inverted window balance system within a window jamb in a window frame. The method includes four basic steps. The first step is to provide an inverted window balance system that includes a rigid U-shaped channel with a plurality of openings in the channel walls for securing the contents in the channel, an extension spring and a system of pulleys disposed within the rigid U-shaped channel, a cord to connect the extension spring via the system of pulleys with the window sash, and a balance shoe. The balance shoe includes a frame, a locking member located at least partially within the frame, a cam in communication with the locking member, and a connecting device for attaching the balance shoe within the rigid U-shaped channel. The frame of the balance shoe has a frame bottom surface, a frame front surface, and two frame edge surfaces. The second step is to insert the inverted window balance system into a jamb track of the window jamb, such that an axis extending along a longitudinal direction of the rigid U-shaped channel is perpendicular to a back wall of the jamb track and an axis that is perpendicular to the two frame edge surfaces is parallel to the back wall while the frame front surface faces a side wall of the jamb track. The third step is to rotate the window balance system within the jamb track 90 degrees about the axis extending along the longitudinal direction of the rigid U-shaped channel, such that the frame front surface faces in a downward direction. The final step is to rotate the window balance system 90 degrees about the axis that is perpendicular to the two frame edge surfaces, such that the frame bottom surface faces in the downward direction.
These and other features of the invention will be made apparent from the following description taken in conjunction with the accompanying drawings.